Mandrel for extrusion press



1.957 M. ARENZ 2,809,750

MANDREL FOR EXTRUSION PRESS Filed Sept. 8, 1952 hlnite States Patent 2,ss,7s0

MANDREL non nxrRUsIoN PRESS Matthias Arenz, Dusseldorf, Germany, assignor to Schloemann Aktiengesellschaft, Dusseldorf, Germany Application September 8, 1952, Serial No. 3%,422

Claims priority, application Germany September 24, 1951 4 Claims. (Cl. 20716) The press mandrel of extrusion presses is subjected during the pressing operation to considerable heating which detrimentally afiects its tensile strength and may therefore easily lead to fractures of the mandrel.

In order to overcome this disadvantage, according to the invention the mandrel is provided, as has already been proposed for instance in the case of stopper rolling mills and the like, with liquid cooling, being fitted with a rearwardly open bore, into which is inserted with tolerance a cooling tube, to which the cooling medium is conveyed through the mandrel carrier. The cooling medium tube is preferably connected with a tube in the mandrel carrier in a fluid-tight, but easily releasable manner with a sliding fit, so that it can be easily removed and changed. It is of special advantage for the cooling medium tube to be inserted telescopically into the tube in the mandrel carrier. The cooling medium tube is furthermore provided in the forward part of the mandrel with lateral outlet openings, so that it is not completely sealed, when it strikes against the forward end of the bore in the mandrel.

The cooling medium enters in front of the mandrel head into the space of annular cross-section between the tube and the surtace of the mandrel bore, so that in its return flow it will cool the internal surface of the mandrel.

Should the mandrel be broken off or crushed during the pressing operation, the cooling medium tube in it being damaged, the tube in the mandrel carrier will remain undamaged and the cooling medium tube in the mandrel, which is connected with the tube in the mandrel carrier by a sliding fit only, can be easily removed and changed for another.

The invention is illustrated in the accompanying longitudinal sectional drawing. The mandrel 1 is fixed in the mandrel carrier 2, for instance with the aid of a thread in. The two constructional parts are of hollow construction, the bore 3 of the mandrel carrier 2 forming the extension of the bore 4 of the mandrel. The cooling medium tube 5 which bears against the mandrel 1 at the head end of the latter extends out of the mandrel 1 at its rear end at 6 and forms with the tube 7 in the mandrel carrier the transitional connection by sliding in it telescopically. Between the tubes 5 and 7 is interposed a short socket tube 3 wmch may be welded to the tube 5. By using socket tubes 8 of different wall thickness it is possible to use cooling mediurn tubes 5 of different diameter, so that the cooling medium tube can be adapted to the different manerels employed. At its forward end the cooling medium tube 5 is provided with large slots 9, through which the cooling medium flowing into the tube, for instance water, enters the annular space 10 between the tube 5 and the bore 4, so as to flow back in the said space.

The double dot and dash lines 11 indicate that at these places sections are omitted. Actually, the various parts in the drawing are considerably longer as compared with their diameter than would appear from the drawing.

I claim:

1. In an extrusion press, a mandrel carrier having an axially extending bore therein, a mandrel carried by said mandrel carrier, extending axially therebeyond and having a rearwardly open, axially extending bore therein in axial alignment with and communicating with the bore in said mandrel carrier, a first tubular member mounted in the bore of said mandrel carrier for conveying a cooling medium therethrough, a second tubular member mounted in and disposed the entire length of the bore of said mandrel but spaced therefrom and having at one end openings adjacent the closed end of said bore in the mandrel, said second tubular member having its other end projecting into said mandrel carrier and extending into the forward end of the first tubular member and co-acting therewith in a manner to provide a telescopically slidable mounting therebetween lying wholly within said mandrel carrier so as to allow the second tubular member to be easily releasable and withdrawable from the first tubular member in an axial direction extending in advance of said mandrel carrier.

2. In an extrusion press, a mandrel carrier having an axially extending bore therein, a mandrel carried by said mandrel carrier projecting forwardly thereof and having an axially extending rearwardly open bore in axial alignment with and communicating with the bore in said mandrel carrier, said second mentioned bore having a closed end adjacent the outer end of the mandrel, a first tube counted within the bore in said mandrel carrier for conveying a cooling medium therethrough, a second tube mounted in the bore of said mandrel, annularly spaced therefrom and having one end projecting rearwardly into said mandrel carrier and extending into the forward end of the first tube, both tubes being so arranged that the first tube telescopes over the second tube in a manner as to provide slidable contact therebetwecn and to allow for relative axial movement to enable the easy withdrawal of the second tube from the first tube in an axial direction extending in advance of said mandrel carrier, said second tube being longer than the entire length of the bore in said mandrel and having a forward end hearing against the closed end of said bore in the mandrel and having lateral openings adjacent the closed end of the bore in the mandrel so as to provide fluid communication with the annular space between the second tube and the interior of the mandrel.

3. An extrusion press as defined in claim 1, and including means interposed between the said tubular members for permitting use of cooling tubes having different diameters so that a cooling medium tubular member can be adapted to difierent mandrels.

4. ln an extrusion press, a mandrel carrier having an axial bore therethrough, said carrier having an outer end having an inwardly extending socket in communication with said bore, a mandrel having one end disposed within said socket and projecting axially beyond the end of said carrier, said mandrel having an axial bore therein in communication with the bore in the mandrel carrier and terminating in a closed end adjacent the opposite end of the mandrel, a fluid cooling medium supply tube of smaller diameter than and mounted within the bore in said mandrel carrier, said supply tube terminating in spaced relation to the inner end of said mandreLa connecting tube having a diameter smaller than and a length in excess of the bore in said mandrel, means providing a telescopic engagement between said tubes at an area wholly within said mandrel carrier and with the outer end of said connecting tube in engagement with the closed end of the bore in said mandrel, said connecting tube having lateral openings therein so that fluid flowing from the supply tube can be discharged into the space between the connecting tube and the interior of the mandrel and returned through the space between the supply tube and the interior of the mandrel carrier whereby the mandrel 3 is fluid cooled and in the event the same is crushed during extrusion with resultant damage to the connecting tube,

the telescopic connection between the connecting tube References Cited in the file of this patent UNITED STATES PATENTS 1,445,139 Jenkins Feb. 13, 1923 ,3 Perks July 26, 1932 Singer Feb. 5, 1935 Hill Feb. 11, 194 1 Findlater Apr. 8, 1941 Hyprath Sept. 25, 1945 Martin et al. Ian. 4, 1954 FOREIGN PATENTS Great Britain Mar. 28, 1929. 

